package com.programmercarl.tree;

/**
 * https://leetcode.cn/problems/merge-two-binary-trees/
 *
 * @author yulongtian
 * @create 2024-12-23 15:26
 */
public class Test16 {
    public static void main(String[] args) {

    }

    public class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;

        TreeNode() {
        }

        TreeNode(int val) {
            this.val = val;
        }

        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }

    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
        // 前序遍历，根左右
        // 根
        if (root1 == null && root2 == null) {
            return null;
        }
        if (root1 == null) {
            return root2;
        }
        if (root2 == null) {
            return root1;
        }
        root1.val = root1.val + root2.val;

        root1.left = mergeTrees(root1.left, root2.left);
        root1.right = mergeTrees(root1.right, root2.right);

        return root1;
    }

}
